Machine for making tire treads



Feb. 18, 1941. w. v. sMlTH MACHINE FORMAKING TIRE TRADS Filed Dec. 1, 1937 '7 Sheets-Sheet 1 I N VEN TOR.

WU/fcr l( Jmi .-1 TTORNEYS Feb. 18, 1941. w. v. SMITH 'MACHINE FOR MAKING TIRE TREADS Filed Dac. 1. 19:57

7 Sheets-Sheet 3 A Mm mm. ,YM f

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Feb. 18, 1941.

MAC'HINE FR MAKING TIRE TREDS 7 Sheets-Sheet 4 Filed Dec. 1. 1937 A.. Q u .111

ATTORNEY` Feb. 18, 1941. w v, sMlTH 2,232,487

' NACHI-NE FOR MAKING TIRE TREADS Filed Deo. l, 1937 7 Sheets-Sheet 5 l N V EN TOR.

Wa/lcr l( Smit/ f7/fha A TTORNEYS.

w. v. SMITH HACHINE FOR MAKING TIRE TREADS Filed Dec. l, 1937 '7 Sheets-Sheet 6 A TTORNEYS.

Feb. 1 8, 1941. w. v. sMrrH MACHINE FOR IAKING TIRE TREADS 7 Sheets-Sheet 7 File'd Dec. 1, 1937 Il l A TTORNEYS.

Patented Feb. 18, 1941 UNITED n STATES 2.232.487 MACHINE Foa mmc 'rum 'ramps Walter V. Smith, South Hadley Falls, liass., as-

signonby mesne assignments, to United States Rubber Company, New York, N. Y., a. corporation of New Jersey Application December 1, 1937, Serial No. 177,646

21 Claims.

This invention relates to the manufacture of pneumatic or other tires, the tread portions of l which are formed of a rubber compound, and

more particularly to the construction of such tread portions.

'I'he principal object of the invention is the provision of a machine for providing a tire tread, formed of suitable tread stock, with inserts of a different material such as a gum stock.

A further object of the invention is to provide a machine having the above general object in view but specifically adapted for inserting strips of material edgewise into the tread portion of a tire.

Other and further objects reside in the means and combinations of means for handling and performing the various operations on the tread and the inserted material and for rendering these operations automatic.

In the accompanying drawings.' which illustrate one embodiment of the invention- Fig. 1 is a side view of the machine with parts broken away to reduce the length of the tread conveyer;

Fig. 2 is an end view looking from the left of Fig. 1 and on a larger scale, parts being broken away; f

Fig. 3 is a side View, omitting the rear portion ofthe tread conveyer, showing the opposite side of the machine from that shown in Fig. 1 and on a larger scale;

Fig. 4 is a sectional View substantially on line 4-4 in Fig. 2;

Fig. 5 is a sectional view substantially on line p 5-5 in Fig. 1 and on a larger scale;

Fig. 6 is a sectional view substantially on line -6-6 of Fig. 2 and on a larger scale;

Fig. 'I is a sectional view substantially on line 1-1 of Fig. 6;

Fig. 8 is a detail view of means for preventing backward movement of the tread feeding means;

Fig. 9 is a detail view showing the tread cutter in front elevation;

Fig. 10 is a `sectional view of the tread knife adjusting means with the parts in a slightly dif ferent position of adjustment from the position of Fig. 4;

Fig. 1l is an end viewof the strip inserting means, parts being in section and parts broken away;

Fig. 12 is a detail plan view of the inserting means; and

Fig. 13 is a'diagram showing the development of the principal cam surfaces with Vthe positions gum rubber I4,

of some of the parts they control diagrammatically indicated.

The embodiment of the invention illustrated is particularly adapted for the edgewise insertion of a succession of strips of gum rubber into a length of tread stock, the gum strips extending transversely of the tread and spaced from. each other longitudinally of the tread. For a preliminary understanding of the general operation reference is made to Fig. 13. As shown in the latter figure, tread length I0 is intermittently advanced around a roll II which imparts a sharp curvature to the tread, placing its `outer surface under tension so that as a cut is made by the knife I2 the cut springs open and remains open for the reception of the inserts. The inserts indicated at I3 are forined from a web or strip of the forward end of which is held between grippers generally indicated at I5-I6. Position d of Fig. 13 at the right of the ligure, shows the parts in their position at the start (and end) of a cycle of operation, the knife I2 and the grippers I5.-I6 being retracted from the tread, the grippers being in line with an opened cut made at a preceding cutting operation. In the first movement of the cycle the knife comes down to form a out in the tread and the grippers advance into the already formed cut to bring the end of the gum stl'ip into adhering contact with the tread stock at the bottom of the cut as shown in position a. The grippers then separate and are Withdrawn backwardly along the gum strip as shown in position b. The grippers move back to initial position where they are closed to again grip the strip and thetstrip is severed by cutter members I8-I9 at a point slightly beyond the gripper jaws, as shown in position c. The knife i I2 is then withdrawn, members I8--I9 retracted, and the tread advanced to bring the parts to the initial position d.

Turning now to Fig. 1, the various instrumentalities are supported by a frame structure which includes spaced pairs 'of uprights 20, 2|, and 22, longitudinal side members 23 and 24, side plates 25, and a rectangular frame member 26.

The tread stock may be fed to the machine by any suitable means. In the form shown (see Fig. 1) tread lengths are spliced end to end on a table member 21, supported on frame members 24 by posts 28 and provided with anti-friction rolls 29. The spliced tread strip passes through a cas adjustment toward and from each other by rotation of the shafts. The shafts 34 are provided with sprockets 35 connected together by a sprocket chain 31 (Figs. 1 and 3) for simultaneous operation by a crank 35, secured to one 5 of the shafts 34. The easing 35 is provided (Fig. 4 and Fig. 5) with an electricalheating element 39 so that the temperature of the tread stock may be controlled if desired.

As a further means for guiding the tread strips lo a chain 33 provided with spikes 35 is trained around sprockets positioned centrally of one of the forward and one of the rear rolls 29. The upper run of the chain rides in a channeled guide 33', Fig. 5, which is supported on the shafts of the rolls 29, which latter are divided in halves.

As the tread length is drawn forward, as presently to be described, it is pressed onto the spikes 35 and the chain is drawn freely along with the tread, the channel 33' holding the chain and tread to their course as they enter the machine.

The tread strip I5 is intermittently drawn forward over rolls 29 and advanced beneath cutter I2 and over roll II (see Fig. 4) by driven feed rolls 45 and 4I respectively engaging the lower and upper faces of the tread strip. The shaft 42 of roll 45 is journaled in side plates 25 of the frame, and one end is provided with a gear 43 (Fig. 3) which meshes with a gear 44 rotatably mounted on a shaft 45 secured to upright 25 of the frame. Intermittent rotation is imparted to gear 44 through a one-way coupling, best shown in Figs. 6 and 7, comprising a drum 45 secured as by screws 41 to the gearv 44 and within which is mounted a notched disk 45.

Spring pressed rollers 49 positioned in the notches 55 of the disk are adapted to wedge between the drum and disk in one direction of rotation of the latter to thereby drive the drum, while running freely in the drum when the disk is rotated in the opposite'dlrection. in a well known manner. A face plate 5l secured to disk 45 by screws 52 is provided with a pin 53 positioned between and in the path of lugs 54 and 55 (Fig. 2) carried by a vertical link rod 55. 'I'he lower lug 55 is threaded on a screw 51, rotatably mounted in brackets 55 secured to the rod 55 and is provided with a squared section 59 for the application of a wrench. By rotation of screw I5'! the position of the lug 55 may be adjusted. A set screw 55 holds lug 55 in adjusted position. 'I'he upper lug 54 is secured to the rod 55 by a set screw 5|. The upper end of linkrod 55 is pivoted to an arm 52 secured to a shaft 53 journaled in bearings 54 secured to uprights 25 of the frame,

which shaft operates the tread knife as will shortly be described. The lower end of rod 55 is pivoted to an arm 55 secured to a. rock shaft 55 driven by means later described. Referring to Fig. 6, lugs 54 and 55 are diagrammatically shown 60 in full lines with relation to pin 53 at the start r of the upward movement of rod 55 and the lugs carried thereby. As the rod moves up, lug 54 leaves pin 53 and the latter in the continued upward movement of the lugs is engaged by lug 55 and moved to dotted line position, thus advancing the gear 44 and rotating feed roll 45 to feed the tread forward the distance desired between cuts. On the return movement of rod 55 the pin is restored to initial position by engagement by the upper lug 54. A light spring 51, connected between a pin 55 secured to plate 5| and a bracket 59 secured to upright 25 (Fig. 2), prevents pin 53 from drifting downward away from lug 54, due to vibration of the machine. Uppery feed roll 4|, Figs. 3 and 4, is mounted on a shaft bearing members,

15 jourhaled in the ends of arms 1| secured to a shaft 12plvoted in bearing lugs 13 formed on side plates 25. One of the arms 1| is extended rearwardly of the shaft 12 as at 14. A threaded rod 15, pivotally connected to the end of extension 14, extends downwardly through an aperture formed in a bracket 15 secured to plate 25. A coiled spring 11, surroundingthe rod 15 and compressed between the bracket 15 and nuts 15 locked on the rod, presses roll 4| into proper drlv- 10 ing engagement with the tread stock while accommodating any slight inequalities in the tread thickness. Nuts 15 locked on the end of rod 15 limit the upward movement of the rod.

The upper feed roll 4| is driven from. and at 15 the same speed as, lower feed roll 45 through a gear 55 (Fig. l) secured to shaft 15 and meshing with a pinion 5|, carried by the adjacent arm 1I, which pinion meshes with a gear 52 rotatably mounted on the pivot shaft 12. Gear 52 is driven 20 by a gear 53 (Fig. 2) mounted on a stub shaft 54 and to which is secured a sprocket 55. connected by a chain 55 to a sprocket 51 (Fig. 2) secured to the end of shaft 42 of the lower feed roll 45. 25

From the feed rolls 45 and 4| the tread strip passes around roll beneath the cutter blade I2. As best shown in Fig. 4 and Fig. 9, blade |2 is carried by a rectangular supporting body formed of spaced cylindrical members and 30 9| connected at intervals by members 92. The blade I2 is held by set screws 9 in the lower cylindrical member 9| which is provided with an electrical heating unit 93 for heating the blade. Upper member 95 is open at its ends and 35 with members 92 acts to radiate the surplus heat, preventing its conduction to the operating parts. 'I'he cutting body is rigidly connected to the lower end of vertical rods 94, preferably in the form of hollow tubes to permit a circulation 40 of air and reduce the conduction of heat to the which extend upwardly through guiding bosses 95 (Fig. 2) formed in a slide 95, and are connected to a yoke bar 51 by nuts 95 threaded on the upper ends of the rom. 45 The yoke bar 91 is connected for vertical adjustment to an operating bar 99 by a screw |55 rotatably mounted at |5| (Fig. 4) in the yoke bar and threaded in the operating bar as at |52. The upper end of screw |55 is provided with an 50 operating handle |53. The ends of bar 93 are connected by links |54 (Fig. 2) to the ends of arms |55 securedto the rock shaft 53, receiving its motion from the rod 55, which as previously described actuates the tread feed rolls. 55

The slide 95 is mounted for adjusting movement in a direction longitudinally of the tread on ways |05 supported by cross members |51 extending between frame members 25. Adjustment of slide 95 is effected by a screw |55 60 threaded into the slide, as at |59 (Figs. 4 and 10) and rotatably mounted in a bearing ||5 secured to the adjacent frame members |01 by machine bolts I|I- Screw |55 is operated by means of a handle II2. Slide 95 also carries a presser roll 65 II3 engaging the tread rearwardly of the knife I2 and roll I I. I/toll ||3 isjournaled inayoke ||4 (Figs. 4 and 9), secured to the lower ends of rods II5 sliding in tubular guides I|5 carried by slide 95. Roll ||3 is forced downwardly into engage- 70 ment with the tread to bend the latter downwardly around the rear portion of roll II, and thus draw the rear wall of the cut away from the rear face oi' the knife, by springs |I1 compressed between yoke lu and the end of guides m. The 75 upper end of rods |I are preferably tied together by a bar I|8 secured to the rods by nuts II9.

After the opened cuts have been filled as later described, the tread passes between a belt `|20 (Fig. 4) running freely around pulleys |2I and |22, and a belt |23 trained around pulleys |24, |25, and |26, belt |23 .being driven at a slightly greater surface speed than the tread around roll II. To keep the belts .properly tensioned, pulley |22 is provided with a conventional take-up indicated at I 21 and pulley |26 is mounted in a sliding bearing |28 held in belt-tightening position by a weight |30 connected to the bearing by a cable I3I passing over a .pulley |32 (Fig. 3). It will be seen that as the tread passes between the Ibelts around pulley |2^| which is of small diameter Ithe outer surface portion of the thread is compressively distorted, thus rmly bonding the inserted strips to the walls of the cuts. From belt |23 the tread is reversed in direction around a roll |35, which strips it from the belt and assures sufficient curvature in this reversal to prevent breaking of the bond between the inserts and the tread rubber. From roll |35 the tread is delivered to a belt |38 supported on a series of rolls |31, the end rolls acting as pulleys for the belt. As best shown in Fig. 1, belt |23 isA driven from feed roll 40. The shaft |38 of pulley |25 is .provided with a sprocket |88 connected by a chain |40 to a sprocket |4| secured to the shaft 42 of roll 40. Belt |36 is driven from gear 82 through a sprocket chain |43, connecting a sprocket |44 secured to gear 82 and a sprocket |45 on the shaft |46 of the rear pulley roll |31 of the belt. Shaft |38 is provided with a crank |41 by which the tread may beadvanced through the machine by hand if desired. Reversemovement of shaft |38 is prevented by a disk |48, secured on shaft |38, the periphery of which runs against a. spring-pressed roll |58 (Fig. 8) which wedges against bracket I 5I upon reverse movement of thedisk.

The means for inserting strips of material such as gum rubber into the cuts is mounted on the rectangular frame 26, which also carries the motor |55 from which the machine as a whole is driven.

The gum supply and inserting devices are carried rby a box-like casting |68 slidably mounted on a rectangular frame comprising flanged cross members I 6| (Fig. 4) connected together at their -ends by members |62 (Figs. 3 and 11). The end member |62 rests upon brackets |63 secured to frame 26. As best shown in Fig. 3, the end members |62 are secured to the brackets |63 by bolts |64 extending through slots |65, permitting adjustment of the frame on the brackets by means of screws |86, extending through ears |61 secured to the bracket, and engaging the cross members |'6|. When the frame has been adjusted on the brackets, Ibolts I64 are tightened to holdit in adjusted position.

Casting |60 (see Fig. 4) is provided with flanges |69 which ride on members |8|, and a bar |10 `bolted to the flanges at I1| is .provided with a downwardly extending lug I`12` threaded on a. shaft |13. Clips |154 bolted to the casting and engaging beneath the flanges of the members. |8I keep the casting |60 in proper relation on the frame.

As best shown in Fig. 11, shaft |13 is joumaled at one end in a bearing |18 secured to the adjacent member |62 and atthe other in a bearing |11 formed in a member |18 secured between frame members I8|. Shaft |13 is provided at one end with a sprocket |80 (see Figs. 3 and 11) connected by a chain I8| to a sprocket |82 mounted on a stub shaft |83 journaled in a bracket |84 supported from member |62. Shaft |83 carries a second sprocket |85 connected by a chain |86 to a sprocket |81 secured on a shaft |88 journaled in a bearing |88 secured to bracket |84. Shaft |88 is provided with a hand wheel |80 by which, -through the chain drive just described, shaft |13 may be rotated to adjust casting |80, and the parts carried thereby, transversely of the machine.

The means for inserting the material in the tread cuts is carried by casting |60. This material, as best shown in Fig. 4, is supplied to the machine in the form of a strip or web I4 of a width equal to the length of the insert desired.

This material, such as a relatively soft gum stock, is woun with a liner |86 to forma roll, indicated at I which is mounted on brackets |88 secured to casting |80. From roll |81 the web and its liner are drawn over a guide roll |88 and` onto a platform 200. Platform 200 is .provided with a slot through which the liner is looped around a roll 202, thus stripping it from the web I4, to which it tends to adhere, so that when the liner reengages the web on the platform 200 the web lies freely on the liner. The rear .portion of the platform `200 may be pivotally mounted to facilitate threading of the liner |86 around roll 202. .From the platform the web and liner pass over a roll 204, the liner being carried around the roll and between it and a roll 205, while the web passes over a guide roll 206 to the inserter. As shown, roll 206 is. driven by a i -belt 2I'I from roll 204. From rolls 204-205 the liner 4.passes around one of a pair of rolls 203 and is wound into a roll 201 about an arbor 208 riding inV guides 209, the roll 201, ing on rolls 203. y

Rolls 204 and 205 (see Fig. 3) are carried on shafts 2|0 and 2I2 respectively, dournaled in sliding bearings 2I3 and 2I4, the bearings 2I3 of roll 204 being pressed toward bearings 2| 4 by adjustable springs (not shown) carried in housings 215.

The shafts of rolls 204 and 205 are respectively provided with intermeshing gears 2I1 and 2I8 (Fig. 2) and the rolls are intermittently operated to advance the liner .|86 and with it the gum strip |4 by means of a friction wheel 220 (Fig. 1) secured to the shaft 2I0 of roll 204. The wheel 220 is engaged by a friction pawl 22| pivoted to one arm of a bell crank 222 pivoted on shaft 2I0. 'I'he other arm of the bell crank is slotted at 223 to slidablyreceive a .pivot pin 224 `held in adjusted position in the slot by a screw 225. Pivot pin 224 is connected by a link 226 to a crank pin 221 adjustably secured in a slot 228 formed in an eccentric disk 228 (Figs. 1 and'll) secured to a shaft 230 which is journaled in casting |60 and is continuously' driven as later described. The liner take-up is driven from a sprocket 23| secured to shaft 2|2 of roll 205 and connected by a chain 232 with a sprocket 233 on the shaft of one of the rolls 203, which rolls are as it forms, rest-l a screen, and roll 235, are carried by the lowermost of a pair of vertically spaced horizontal frames 245 and 24|, respectively provided at their forward edges with gripper bars i and I5. 'I'he forward end of the gum strip extends between the bars |5|5 and is gripped by them when frames 245 and 24| are moved toward. each other. The forward end of frames 24524| are connected together at each side by a pair of lazy-tong links 245, the members of which are connected at one end to the frames by a pin and slot connection 245 and at the other end are pivoted to the frame at 241. 'I'he forward end of frames 245-24I are supported on a carriage 245 provided with lugs 245 in which the pivots 255 of the links 245 are journaled. Carriage 245 is Slidably mounted on' guides 25| (Fig. 11) formed on casting |55, and is reciprocated toward and from the tread by means of a link 252 connecting the carriage with the free end of a lever 253 pivoted at 254 to the bar |15. Lever 253 is provided with a cam roll 255 riding in a cam groove 255 formed in a cam 251 secured to the shaft 235 previously mentioned. Link 252 is spring cushioned as at 2515 and is adjustably connected to lever 253- by means of. a slot 255. By'adjustment of this link the length of stock projecting beyond the grippers can be controlled.

The frames 245 and 24| are moved toward and from each other to grip and release the gum strip, by means of arms 255 secured on a rock shaft 25| journaled in brackets 252 mounted on casting |55. As best shown in Fig. 4, the opposite ends of arms 255 are connected to the side members of frames 245 and 24| by pin and slot connections 253. The end of shaft 25| is provided with a crank arm 255, Figs. 3 and 11, connected by a link 255 to the free end of a lever 251 pivoted at 255 (Fig. ll) to casting |55. Lever 251 is provided with cam roll 255 riding in groove 215 of a cam 21| secured to shaft 235. 'I'he connection between link 255 and lever 251 is cushioned by adjustable springs 212, thus cushioning the operation of the grippers.

Cams 251 and 21| are so timed that, as previously described, the grippers |5-I5 engage the end of strip |4 when carriage 245 is in retracted position, and the forward movement of the carriage carries the strip into the cut and presses its end into adhering contact with the bottom of the tread cut. As the gripper carriage starts its return, the grippers are opened and move back alo'ng the strip, closing again when the carriage reaches its rearmost position. At this point the end portion of the gum strip, now positioned in the tread cut, is severed closely adjacent the grippers.

The means for so severing the gum strip comprises a cutting blade |5 and a cooperating platen I9. mounted on the forward ends of pairs of arms 211 and 215 pivoted on shaft 25| (Figs. 3, l1, and 12). The arms 211 and 215 are each made adjustable as to length by being formed in two parts connected together by bolt and slot connections 215. The cutter arms 211 are provided with downwardly extending lugs 255 which are connected by adjustable links 25| to lever arms 252 secured on opposite sides of the machine to a rock shaft 253 which is journaled in the sides of casting |55. The cutter arms 211 are connected by a brace 254. Each arm 215 is provided with a lug 255 (see Figs. 3, 4, and 1l) connected by adjustable links 255 to lever arms 251 integral with lever 252 but extending in opposite directions. It will thus -be seen that as shaft 253 is rocked, the blade I5 and platen l5 are swung toward and Blade I5 and platen I5 are respectively'- from each other. As shown in Fig. 4, blade |5 is provided with an electrical heating coil 255. The desired rocking movement is imparted to shaft 253 by an arm 255 secured to one end of the shaft and provided with a cam roll 25| riding in l a groove 252 formed in a cam 253. Cam 253 is adjustably secured, as at 254, in back to back relation, to cam 21|, which in turn is mounted on drive shaft 235.

Power is supplied to the shaft 235 from the motor |55 which drives a shaft 455 through a conventional gear reduction unit 45|. Shaft 455 is provided with a sprocket 452 connected by a chain 453 to a sprocket 454 rotatably mounted on a shaft 455 journaled in suitable bearings on frame 25. Sprocket 454 'is provided'with a clutch mem-ber 455 (Fig. 11) adapted to be engaged by a clutch member 451 splined on shaft 455 and movable into driving engagement with the clutch member 455 by means of a clutch shifting lever 455 (Fig. 3). Slidably splined on shaft 455 is a sprocket 4|5 connected by a chain 4|| to a sprocket 4|2 secured on cam shaft 235. As previously described, the casting |55 in which shaft 235 is mounted is adjustable transversely of frame 25 and, in order to maintain sprockets 4|5 and 4|2 in alignment, sprocket 4|5 is constrained to move along shaft 455 in company with the movement of sprocket 4|2 by means of a fork 4|4, bolted to casting |55 at 4|5, vand engaging in groove 4|5 formed in the hub of sprocket 4|5.

A sprocket 4|5 fixed to shaft 455 is connected by a chain 4|5 toa sprocket 425 mounted on shaft 42| secured in spaced vertical 'brackets 422 mounted on frame 25 by bolts 423. Sprocket 425 is secured to a cam 425, Figs. 2, 3, and 4, also mountedon shaft 42| and provided with a cam groove 425 in which rides a cam roll 421 counted on-one end of an adjustable link 425 and held in proper position in the cam groove by a guide arm 425. Link 425 is pivotally connected to the upper end of a lever 435 connected to rock the shaft 55 and from which, as previously described, the tread feeding, guiding, and cutting means receive their motion. To permit the various devices to be turned over by hand, if desired, shaft 455 is provided with a hand crank 43 I.

As best shown in Figs. 2, 3, and 1l, frame 25 is provided with bearing members 435 Slidably mounted on spaced horizontal rods 435 secured at one end to across bar 431 secured to uprights 25 of the main frame and at their outer end to angle irons 435. A bar 434 and irons 435 similarly support a threaded rod 435 upon which a nut 445 travels. Nut 445 is rotatably mounted in a plate 44| secured to frame 25, and is formed with sprocket teeth 442. 'I'he nut 445 is adapted to be rotated to move the frame 25 along rods 435 by a sprocket chain 443 engaging sprocket 442 and passing around a sprocket 444 mounted on a stub shaft 445 journaled in frame 25. Stub shaft us is provided with a hand vmee1 us.

The normal operative relation of frame 25 and the main frame is shown in Fig. 3 and the frames are releasably held in this position by swinging bolts 445 pivoted to the uprights 25 and engaging in slots 445 formed in frame 25. The exact relative position of frame 25 to the main frame can be nicely adjusted through nuts 555 threaded on bolts 445 and adjustable stops 55| threaded in the frame 25 and engaging uprights 25 of the main frame.

It is sometimes desirable to operate the various instrumentalities, for the purposes of adjustment, with the frame 25 in retracted position, and

llli

for this purpose link 428 is extended beyond its normal point of connection to the lever lill, as indicated at 502, and its free end is provided with an opening 503 for attachment to lever 430.

The rtread strip is delivered from the machine (Fig. 1)` onto a series of anti-friction rolls 505 journaled in frame members, and from which it may be removed `for subsequent treatment in any desired manner. As shown, the end of Ithe strip'is looped back onto the` end portion of the upperset of rolls 29 and against a stop 5 positioned a predetermined distance from a knife guide 501 provided with slots 508 through which the strip may 4be `quickly severed into treads `of appropriate length. i

It will be understood that to provide the most satisfactory tread of the characterthe above described machineis designedto produce, the inserts must be accurately arranged in the tread. For best results the cuts must be accurately spaced and the inserts must be accurately and smoothly placed in the cuts. In the embodiment of the invention as disclosed, a complete adjustment of the various parts with respect to the materials operated upon and to each other `is provided, as well as means for securing'accurate timing of their operations.

Obviously, various changes and modifications can be made in the details of commotion of the machine without departing from the scope of the invention, and it will be understood that the following references to certain preferred features are not to be construed as a limitation on claims not specifically directed thereto. 1 Itis well known that freshly cut rubber surfaces, and particularly where the cutting has been done with a heated knife, are more readily bonded together than where the cuts are not fresh or are made with a cold knife. For this reason I prefer that the knives for cutting the tread and gum stocks shall be heated. Moreover, I have found it to be desirable that the tread which is relatively massiveshall be warm at the time the'insert-receiving cuts are made. I have further found that it is advantageousto form the cut in the tread slowly-that is, to let the heated tread knife 'sink into the tread. The advance of the knife is not so slow as to burn the rubber, but is such that the resilience of the rubber is temporarily destroyed as the knife advances. Such procedure makes possible much more accuracy in the depth of the cut, requires ,less power, and leaves the walls of the cut in better condition for satisfactory bonding with the inserted material. The insert can be placed immediately in the cut as. or as soon as, the knife is withdrawn, but slight delay in the insertion of the gum strip, such as that allowed-by advancing the tread one or two cuts before inserting the gum stock, tends to improve the bonding between the gum and tread stocks. This delay in the insertion of the gum stock also makes it possible to perform the inserting operation while the knife is engaged in the tread strip, theknife thus assisting in holding the tread strip stationary during the inserting operation `and further assuring the accuracy of the positioning of the cuts with reference to the inserting mechanism.

I claim:

1. A tread making machine which comprises means to form a cut in a strip of tread stock, means to open said cut, means to advance an end of a thin strip of material into adhering contact with the bottom of the cut, and means to sever the end portion from said thin strip of material" to leave said severedportion in the cut.

2. A tread making machine which comprises means to distort a strip of tread stock to place the outer portion thereof under tension, means to form a cut in the distorted portion of the tread whereby the cut opens under the tension imposed by the distortion, and means to insert a thin piece of filler material edgewise into the so opened cut.

3. A tread making machine whichcomprises means to advance a strip of tread stock along a path curved in the plane of tread travel to place the outer portion thereof under tension, a cutting means for forming a cut in the so tensioned tread whereby the walls of the cut separate under said tension, and means acting prior to the release of the tread strip from tension to position la strip of ller material between the separated walls of the cut.

4. A tread making machine which comprises means for intermittently advancing a strip of` tread stock, a reciprocable cutter beneath which the tread strip passes, means to tension the outer portion of the tread beneath the cutter, means to reciprocate the cutter to press the cutter into the tensioned portion of the tread, said tension acting to separate the walls of the cut as the cutter advances into the tread stock and to maintain said walls separated upon withdrawal of the cutter and during further advance of the tread strip, and means to insert a thin piece of filler material edgewise into the open cutto be gripped by the walls thereof upon release of the tread strip from tension.

5. A tread making machine which comprises means forintermittently advancing a strip of tread stock, a roll around which the strip advances and adapted to place the outer portion of the tread strip under tension, a heated cutter, means to reciprocate the cutter during the periods of rest of the strip to form a series of cuts in the tensioned portion of the strip, said tension acting to separate the walls of the cuts as the cutter advances into the tread and to maintain the walls separated upon withdrawal of the cutter and during successive advances of the tread strip, means operative during the periods of rest of the strip to successively project an end of a thin strip of material into adhering contact with the bottom of each previously formed cut as it comes to rest in front of the projecting means, and means to sever successive end portions from said thin strip to leave said portions in the cuts.

6. A tread making machine which comprises means to form a cut in a strip of tread stock, means to open said cut, gripping means engaging a strip of filler `material adjacent its end and advancing it into adhering contact with the bottom of the, cut, means to release the gripping means and heated means to sever the portion of the nner strip within the cut from/the body of the strip.

7. A tread making machine which comprises means to form a cut in a strip of tread stock, means to open said cut, a pair of spaced cutting members, means to advance a strip of filler material between said cutters and into the open 8. A tread making machine which comprises means to form a cut in a strip of tread stock, means to open said cut, gripping members, means to reciprocate said gripping members into and Cil ' out of said open cut, gripper actuating means to close said grippers when positioned outwardly of the cut to thereby engage a strip of filler material adjacent the end of said strip and advance the end portion of the strip into the cut upon forward -movement of the grippers, and to open said grippers upon return movement of the latter to leave said end portion of the strip in the cut, a pair of spaced cutting members between which the grippers pass, and means to actuate said cutting members to sever the portion of the filler strip within the cut from the body of the strip.

9. A tread making machine which comprises means to advance a strip of tread stock along a path curved in the plane of tread travel to place the outer portion thereof under tension, a cutting means for forming cuts in the so tensioned tread whereby the walls of the cuts separate under said tension, means acting prior to the release of the tread strip from tension to position a strip of filler material between the separated walls of the cuts, and means for thereafter reversing the curvature of the tread strip during a subsequent portion of its travel to press the walls of the cuts into adhering contact with the filler strips.

10. In a tread making machine, a heated cutting member, means to advance said cutting member into the tread at a speed sumciently slow so that the heat of the knife acts to destroy the elasticity of the rubber compound as the knife advances, and means to apply tension to the tread strip transversely of the. line of cut to separate the walls of the cut from the knife as the knife advances into the rubber.

11. In a tread making machine, a heated cuting member, means to advance said cutting member into the tread at a speed sufficiently slow so that the heat of the knife acts to destroy the elasticity of the rubber compound as the knife advances, means to apply tension to the tread strip transversely of the line of cut to separate the walls of the cut from the knife as the knife advances into the rubber, and means to insert a strip of filler material into the cut while the walls of the cut are still tacky from the heat of the knife.

12. In a tread making machine a roll about which the tread is intermittently advanced, a cutting member movable substantially radially toward and from the roll to form transverse cuts in the tread, means movable substantially radially toward and from the roll and positioned substantially 90 from the cutting member for inserting a ribbon of ller material in the cuts formed by the cutting member, and means to actuate said cutting member and -inserting means contemporaneously.

13. In a tread making machine, means to intermittently advance a strip of tread stock, means to form a cut in said strip, a carriage, means for moving said carriage toward and fromvthe tread, gripping means mounted on said carriage for engaging a strip of illler material and advancing it into said cut, means to sever the portion of the filler strip within the cut from the body of the ller strip, a common support for said carriage and ller strip severing means, and manually operated means for moving said support transversely of the tread while the parts carried by the support are in operation.

14. In a tread making machine, means to intermittently advance a strip of tread stock, means to form cuts in said strip, a carriage, means for moving said carriage toward and from the tread, gripping means mounted on said carriage for engaging a strip of filler material and advancing it into said cut, means to sever the portion of the filler strip within the cut comprising spaced cutting members between which the grippers advance, a common support for the gripping and severing means, means for adjusting the position of said support relative to the tread,.and means to adjust the travel of the carriage with respect to the cutting means.

15. In a tread making machine. a reciprocabie knife support. a knife adjustably mounted on said support, means for advancing a tread strip beneath the knife, actuating means to move the knife support toward and from the tread to cause the knife to form a cut in the tread strip of a depth determined by the adjustment of the knife with respect to its support, and a one-way drive for the tread strip advancing means, having a lost motion connection with the knife actuating means, for advancing the tread during the return movement of the knife from cutting position, the amount of lost motion being suilicient to permit the knife to clear the tread strip before advance of the latter.

16. A tread making machine which comprises means to form a cut in a strip of tread stock, means to open said out, means for supplying filler material for the cut, a carriage movable between the tread stock and said filler supply means, and means on the carriage for receiving material from the supply means and delivering 5 it into the opened cut.

1'1. A machine for inserting material in a body of unvulcanized rubber which comprises, means to form a cut in said body, means to spread the walls of the cut, and conveyer means bodily movable into and out of the spread cut to transport said material into and deposit said material in the cut.

18. A machine for inserting material in a body of unvulcanized rubber which comprises means to form a plurality of spaced cuts in a body of unvulcanized rubber, means to temporarily apply tension to the strip to hold the cuts open, and conveyer means bodily movable into and out of the so opened cuts to transport said material into and deposit material in each of the cuts.

19. A machine for inserting material in a body of unvulcanized rubber which comprises means to form a cut in a body of unvulcanized rubber, means to insert the end portion oi' a strip of material into the cut, and means to sever the inserted portion from the strip.

20. In a machine for inserting material into a cut formed in a body of unvulcanized rubber, means to spread the walls of the cut without obstructing the interior of the cut, means to feed material into the cut while the walls are so spread, and means to vary the amount of material placed in the cut by the feeding means.

21. In a machine for inserting material into a cut formed in a body of unvulcanized rubber, means to spread the walls of the cut without obstructing the interior oi the cut, means to feed a fiat -strip of material into the cut while the walls are so spread, and means to predetermine the position of the strip in the cut.

WALTER V. SMITH. 

